expansion tank

kpc_40

any other vents in the system? May be bets to go w/ the diaphragm tank....kpc

Jay_38

expansion tank

I had a service call on a compression style expansion tank that kept waterlogging. Feed piped into boiler supply suction side of the pump. The expansion tank was piped into the return. I installed an ATF 20 airtrol fitting and teed the expansion tank with the cold fill on the boiler supply and plugged the old 1 inch return tapping that was used for the tank. I piped the expansion tank with 1" copper above the coldfill and pitched the pipe up towards the compression tank airtrol fitting. I replaced the sight glass assembly and filled the tank last then fired up the boiler the water line rose above the 2/3 level but did not fill all the way up. The tank has been there for years it is made by John Wooden Company. I e-mailed them and they weren't 100% of the size but it is either a 80 or 100 gallon. When the boiler fires up the pressure rises from 12 psig to 25 psig. It is not popping the relief valve but a 13 psig rise is too much. This building is very big and there are no blue prints so I have no idea how I can calculate all this piping to see if this tank is undersized. Re-piping and installing an airtroll has helped but I am concerned that eventually it is going to come back in that the little air pocket I have will be gone before too long. My last ditch idea was to install a watts bladder type expansion tank 211 gallon capacity which is at least double what I have now but I already was wrong once don't want to do it again I might be missing something.There is no air seperator on the boiler piping 4" black iron and there is not enough room for the 18" approach piping. Any help would be appreciated? Thank You Jay.

Big Ed_4

Check the gauge glass.....

.... asembaly and tanks for leaks. Pick up bubble leak search .